Without seeing your trailer I can only speak in generalities. I wouldn't say it's difficult, but it is a lot of "hard work." There are many products/tools/safety items to buy, and there are a lot of steps, many dusty and smelly and toxic. You have to be pretty diligent about doing things properly and not rushing to the fun steps and skipping the prep, sanding, etc.
You also need a dry, temperature-controlled place to work for some (but not all) of the steps.
To summarize, there is no one individual step that is all that difficult or demanding - or out of reach for the common person - but overall it is a job somewhat demanding of stamina, conscientiousnes, time, and money.
One note is that you should not spray two-part paints "at home" without a true, supplied air respirator. They can be very toxic and dangerous, even in small, quick doses. You can roll and tip a two-part paint
with a good cartridge respirator (which you would already have from fiberglassing and prepping). You can also roll and tip or spray a one-part paint
. But for myself, after all the prep work, I would want the longevity/shine of a two-part paint.
PS: In re-reading your post I see you did not mention re-painting in the body of your post, but did in the title
, so I'm not sure if I'm answering your question exactly; however, after you stripped and repaired the fiberglass, it would be the next logical step.